Not applicable.
Not applicable.
Not applicable.
This invention is directed to organic oil-in-water (O/W) emulsions, and to certain compositions containing such organic O/W emulsions in combination with a salt, an alcohol, a solvent, or a combination of the salt, the alcohol, and the solvent.
Emulsions prepared with conventional organic surfactants are generally not stable in the presence of an alcohol or a solvent. When an ionic surfactant is used, the emulsions are not stable in the presence of salts. In fact, salts, lower alkyl alcohols, and certain organic solvents, are routinely used to break emulsions into separate phases to analyze content.
However, it has been found that when a silicone polyether is used to make an organic oil-in-water emulsion or a silicone polyether is added to a previously prepared organic oil-in-water emulsion, that the organic oil-in-water emulsion is stable in the presence of a salt, an alcohol, an organic solvent, or a combination thereof. Such stability is an advantage and benefit in personal care, household care, automotive care, and coating industry applications.
U.S. Pat. No. 5,216,070 (Jun. 1, 1993) is directed to preparation of organic oil-in-water emulsions using silicone polyethers, however it arrives at the composition by a complex inversion process in which a water soluble organic monomer is dispersed in an aqueous phase. In contrast, the method according to the present invention achieves a similar result directly without inversion, and uses instead water insoluble or only partially water soluble organic monomers in an oil phase.
U.S. Pat. No. 5,443,760 (Aug. 22, 1995) is directed to oil-in-water emulsions containing silicone polyethers, but the oil phase of the oil-in-water emulsion includes silicone oils rather than only organic oils.
U.S. Pat. No. 5,891,954 (Apr. 6, 1999) is directed to silicone oil-in-water emulsions prepared with silicone polyethers which are stable in the presence of an alcohol, however the silicone polyethers are only post added to previously prepared silicone oil-in-water emulsions, and it fails to teach using only organic oils in the oil phase of oil-in-water emulsion or the stability of the emulsions in the presence of salt and solvents.
U.S. Pat. No. 5,969,038 (Oct. 19, 1999) is directed to silicone oil-in-water emulsions which are stable in the presence of a salt, but it does not use silicone polyethers, and it fails to teach using only organic oils in the oil phase of the oil-in-water emulsion, as well as the stability of the emulsions in the presence of alcohols and solvents.
This invention relates to new compositions of matter. In particular, there are four compositions. In a first embodiment, a composition is prepared by combining a salt component and an organic O/W emulsion which contains an organic oil, a surfactant(s), and water. In a second embodiment, a composition is prepared by combining an alcohol component and the organic O/W emulsion containing the organic oil, surfactant(s), and water. In a third embodiment, a composition is prepared by combining a solvent component and the organic O/W emulsion containing the organic oil, surfactant(s), and water. In a fourth embodiment, a composition is prepared by combining the salt component, the alcohol component, the solvent component, or combinations thereof, and the organic O/W emulsion containing the organic oil, surfactant(s), and water.
These and other features of the invention will become apparent from a consideration of the detailed description.
Not applicable.
This invention is based on the unexpected discovery that when silicone polyethers are used to prepare organic oil-in-water emulsions, the resulting formulations are stable in the presence of salts such as calcium chloride and aluminum sulfate; alcohols such as methanol, ethanol, propanol and isopropanol; and organic solvents such as pentane.
The silicone polyether can be the only emulsifier used in making these emulsion; it can be used in combination with other organic type surfactants; or it can be post added to a previously prepared emulsion. The silicone polyether can be used to make organic oil-in-water microemulsions which are also stable in the presence of such salts, alcohols, and solvents.
Silicone Polyether (SPE) Surfactant
The silicone polyether is generally water soluble or water dispersible. It can have a rake type structure wherein the polyoxyethylene or polyoxyethylene-polyoxypropylene copolymeric units are grafted onto the siloxane backbone, or the SPE can have an ABA block copolymeric structure wherein A represents the polyether portion and B the siloxane portion of an ABA structure.
Silicone polyethers suitable for use herein have the formula MD0-1,000Dxe2x80x21-100M, most preferably the formula MD0-500Dxe2x80x21-50M, where M represents monofunctional unit R3SiO1/2, D represents difunctional unit R2SiO2/2, and Dxe2x80x2 represents difunctional unit RRxe2x80x2SiO2/2. In these formulas, R is an alkyl group containing 1-6 carbon atoms or an aryl group, and Rxe2x80x2 is an oxyalkylene containing moiety. The Rxe2x80x2 groups may contain only oxyethylene (EO) units; a combination of oxyethylene (EO) and oxypropylene (PO) units; or a combination of oxyethylene (EO) units, oxypropylene (PO) units, and oxybutylene (BO) units. Preferred Rxe2x80x2 groups include oxyalkylene units in the approximate ratio of EO3-100PO0-100, most preferably in the ratio EO3-30PO1-30.
Rxe2x80x2 moieties typically includes a divalent radical such as xe2x80x94CmH2mxe2x80x94 where m is 2-8 for connecting the oxyalkylene portion of Rxe2x80x2 to the siloxane backbone. Such moieties also contain a terminating radical for the oxyalkylene portion of Rxe2x80x2 such as hydrogen, hydroxyl, or an alkyl, aryl, alkoxy, or acetoxy group.
Silicone polyethers useful herein can also be of a type having the formula Mxe2x80x2D10-000Dxe2x80x20-100Mxe2x80x2, most preferably the formula Mxe2x80x2D10-500Dxe2x80x20-50Mxe2x80x2, wherein Mxe2x80x2 represents monofunctional unit R2Rxe2x80x2SiO1/2, D represents difunctional unit R2SiO2/2, and Dxe2x80x2 represents difunctional unit RRxe2x80x2SiO2/2. In these formulas, R can be an alkyl group containing 1-6 carbon atoms or an aryl group, and again Rxe2x80x2 represents an oxyalkylene containing moiety. As noted previously, Rxe2x80x2 groups typically contain only oxyethylene (EO) units or combinations of oxyethylene (EO) and oxypropylene (PO) units. Such Rxe2x80x2 groups include these oxyalkylene units in the ratio EO3-100PO0-100, most preferably EO3-30PO1-30.
As also noted previously, Rxe2x80x2 moieties typically include a divalent radical xe2x80x94CmH2mxe2x80x94 where m is 2-8 for connecting the oxyalkylene portions of Rxe2x80x2 to the siloxane backbone. In addition, the moiety Rxe2x80x2 contains a terminating radical for oxyalkylene portions of Rxe2x80x2 such as hydrogen, hydroxyl, an alkyl, aryl, alkoxy, or acetoxy group.
In addition, silicone polyethers useful herein can be of a type having the formula MD0-1,000Dxe2x80x20-100Dxe2x80x31-1,00M wherein Dxe2x80x3 represents difunctional unit RRxe2x80x3SiO2/2, and Rxe2x80x3 is an alkyl group containing 1-40 carbon atoms. M, D, Dxe2x80x2, and R, are the same as defined above.
Table I shows some representative silicone polyethers according to such formulas, and these compositions are referred to in the accompanying Examples.
Oil Component
For purposes of this invention, the term xe2x80x9corganic oilxe2x80x9d is intended to mean a non-silicon atom containing organic oil including synthetic oils and natural oils derived from animal, vegetable, or mineral sources. Representative of some suitable non-silicon atom containing organic oils which can be used are almond oil, apricot kernel oil, avocado oil, cacao butter (theobroma oil), carrot seed oil, castor oil, citrus seed oil, coconut oil, corn oil, cottonseed oil, cucumber oil, egg oil, jojoba oil, lanolin oil, linseed oil, mineral oil, mink oil, olive oil, palm oil, kernel oil, peach kernel oil, peanut oil, rapeseed oil, safflower oil, sesame oil, shark liver oil, soybean oil, sunflower seed oil, sweet almond oil, tallow (beef) oil, tallow (mutton) oil, turtle oil, vegetable oil, whale oil, and wheat germ oil; alkanes generally containing about sixteen or more carbon atoms such as hexadecane; aromatic hydrocarbons such as benzene and toluene; fluorinated hydrocarbons such as perfluorocyclohexane, perfluorohexane, perfluorododecane, and perfluoropolyethylene oxide; esters such as isopropyl laurate, isopropyl palmitate, hexyl laurate, isopropyl myristate, myristyl myristate, cetyl myristate, 2-octyldecyl myristate, isopropyl palmitate, 2-ethylhexyl palmitate, butyl stearate, decyl oleate, and 2-octyldodecyl oleate; glycol ester oils such as polypropylene glycol monooleate and neopentyl glycol 2-ethylhexanoate; and polyhydric alcohol ester oils such as isostearate triglyceride and cocofatty acid triglycerides.
Also included among the types of non-silicon atom containing organic oil which can be used herein are unsaturated monomeric organic compounds such as styrene, butyl acrylate, butadiene, vinylidene chloride, vinyl chloride, ethylene, methyl methacrylate, ethyl acrylate, vinyl acetate, methyl acrylate, and acrylonitrile; and their low molecular weight polymerization products such as polystyrene and polyethylacrylate. Most preferred, are water-insoluble monomers such as styrene, and monomers generally considered only partially water soluble.
The organic oil used in emulsions according to the invention can be a composition having a linear or branched chain, it can be saturated or unsaturated, or it can be a hydrocarbon or fluorocarbon type of organic oil. A mixture of different organic oils can also be employed.
Additional and/or Optional Organic Surfactant
While the silicone polyether is capable of functioning as the sole emulsifying agent, other optional and additional organic surfactants can be included in combination with the silicone polyether surfactant, if desired.
Such other surfactant can be a nonionic, cationic, anionic, amphoteric (zwitterionic), or a mixture of such surfactants. The nonionic surfactant should be a non-silicon atom containing nonionic emulsifier. Most preferred are alcohol ethoxylates R2-(OCH2CH2)cOH, most particularly fatty alcohol ethoxylates. Fatty alcohol ethoxylates typically contain the characteristic group xe2x80x94(OCH2CH2)cOH which is attached to fatty hydrocarbon residue R2 which contains about eight to about twenty carbon atoms, such as lauryl (C12), cetyl (C16) and stearyl (C18). While the value of xe2x80x9ccxe2x80x9d may range from 1 to about 100, its value is typically in the range of 2 to 40.
Some examples of suitable nonionic surfactants are polyoxyethylene (4) lauryl ether, polyoxyethylene (5) lauryl ether, polyoxyethylene (23) lauryl ether, polyoxyethylene (2) cetyl ether, polyoxyethylene (10) cetyl ether, polyoxyethylene (20) cetyl ether, polyoxyethylene (2) stearyl ether, polyoxyethylene (10) stearyl ether, polyoxyethylene (20) stearyl ether, polyoxyethylene (21) stearyl ether, polyoxyethylene (100) stearyl ether, polyoxyethylene (2) oleyl ether, and polyoxyethylene (10) oleyl ether. These and other fatty alcohol ethoxylates are commercially available under names such as ALFONIC(copyright), ARLACEL, BRIJ, GENAPOL(copyright), LUTENSOL, NEODOL(copyright), RENEX, SOFTANOL, SURFONIC(copyright), TERGITOL(copyright), TRYCOL, and VOLPO.
Cationic surfactants useful in the invention include non-silicon atom containing compounds having quaternary ammonium hydrophilic moieties in the molecule which are positively charged, such as quaternary ammonium salts represented by R3R4R5R6N+Xxe2x88x92 where R3 to R6 are alkyl groups containing 1-30 carbon atoms, or alkyl groups derived from tallow, coconut oil, or soy; and X is halogen such as chlorine or bromine, or X can be a methosulfate group. Most preferred are (i) dialkyldimethyl ammonium salts represented by R7R8N+(CH3)2Xxe2x88x92, where R7 and R8 are alkyl groups containing 12-30 carbon atoms, or alkyl groups derived from tallow, coconut oil, or soy; and X is halogen or a methosulfate group; or (ii) monoalkyltrimethyl ammonium salts represented by R9N+(CH3)3Xxe2x88x92 where R9 is an alkyl group containing 12-30 carbon atoms, or an alkyl group derived from tallow, coconut oil, or soy; and X is halogen or a methosulfate group.
Representative quaternary ammonium salts are dodecyltrimethyl ammonium bromide (DTAB), dodecyltrimethyl ammonium chloride, tetradecyltrimethyl ammonium bromide, tetradecyltrimethyl ammonium chloride, hexadecyltrimethyl ammonium bromide, hexadecyltrimethyl ammonium chloride, didodecyldimethyl ammonium bromide, dihexadecyldimethyl ammonium chloride, dihexadecyldimethyl ammonium bromide, dioctadecyldimethyl ammonium chloride, dieicosyldimethyl ammonium chloride, didocosyldimethyl ammonium chloride, dicoconutdimethyl ammonium chloride, ditallowdimethyl ammonium chloride, and ditallowdimethyl ammonium bromide. These and other quaternary ammonium salts are commercially available under names such as ADOGEN, ARQUAD, SERVAMINE, TOMAH, and VARIQUAT.
Examples of non-silicon atom containing anionic surfactants include sulfonic acids and their salt derivatives such as dodecylbenzene sulfonic acid (DBSA); alkali metal sulfosuccinates; sulfonated glyceryl esters of fatty acids such as sulfonated monoglycerides of coconut oil acids; salts of sulfonated monovalent alcohol esters such as sodium oleyl isothionate; amides of amino sulfonic acids such as the sodium salt of oleyl methyl tauride; sulfonated products of fatty acid nitriles such as palmitonitrile sulfonate; sulfonated aromatic hydrocarbons such as sodium alpha-naphthalene monosulfonate; condensation products of naphthalene sulfonic acids with formaldehyde; sodium octahydro anthracene sulfonate; alkali metal alkyl sulfates such as sodium lauryl (dodecyl) sulfate (SDS); ether sulfates having alkyl groups of eight or more carbon atoms; and alkylaryl sulfonates having one or more alkyl groups of eight or more carbon atoms.
Commercial anionic surfactants useful in this invention include triethanolamine linear alkyl sulfonate sold under the name BIO-SOFT N-300 by the Stepan Company, Northfield, Ill.; sulfates sold under the name POLYSTEP by the Stepan Company; and sodium n-hexadecyl diphenyloxide disulfonate sold under the name DOWFAX 8390 by The Dow Chemical Company, Midland, Mich.
Surfactants classified as amphoteric or zwitterionic include cocoamphocarboxy glycinate, cocoamphocarboxy propionate, cocobetaine, N-cocamidopropyldimethyl glycine, and N-lauryl-N-carboxymethyl-N-(2-hydroxyethyl)ethylene diamine. Other suitable amphoteric surfactants include the quaternary cycloimidates, betaines, and sultaines.
The betaines have the structure R11R12R13N+(CH2)nCOOxe2x88x92 wherein R11 is an alkyl group having about twelve to eighteen carbon atoms or a mixture thereof, R12 and R13 are independently lower alkyl groups having one to three carbon atoms, and n is an integer from one to four. Specific betaines are xcex1-(tetradecyldimethylammonio)acetate, xcex2-(hexadecyldiethylammonio)propionate, and xcex3-(dodecyldimethylammonio)butyrate.
The sultaines have the structure R11R12R13N+(CH2)nSO3xe2x88x92 wherein R11, R12, R13, and n are as defined above. Specific useful sultaines are
3-(dodecyldimethylammonio)-propane-1-sulfonate, and
3-(tetradecyldimethylammonio)ethane-1-sulfonate.
Representative amphoteric surfactants are products sold under the names MIRATAINE(copyright) by Rhone-Poulenc Incorporated, Cranberry, N.J.; and TEGO BETAINE by Goldschmidt Chemical Corporation, Hopewell, Va. Imidazoline and imidazoline derivatives sold under the name MIRANOL(copyright) by Rhone-Poulenc Incorporated, Cranberry, N.J. may also be employed.
Salt Component
As used herein, the term xe2x80x9csaltxe2x80x9d is intended to mean an inorganic salt or an organic salt, including compounds commonly referred to as electrolytes.
Some examples of suitable inorganic salts include calcium chloride, magnesium sulfate, magnesium chloride, sodium sulfate, sodium thiosulfate, sodium chloride, sodium phosphate, ammonium chloride, ammonium carbonate, iron sulfate, aluminum sulfate, aluminum chloride, aluminum chlorohydrate, aluminum sesquichlorohydrate, aluminum dichlorohydrate, aluminum zirconium tetrachorohydrex glycine, aluminum zirconium trichlorohydrate, aluminum zirconium tetrachlorohydrate, aluminum zirconium pentachlorohydrate, and aluminum zirconium octachlorohydrate.
Some examples of suitable organic salts include sodium aluminum lactate, sodium acetate, sodium dehydroacetate, sodium butoxy ethoxy acetate, sodium caprylate, sodium citrate, sodium lactate, sodium dihydroxy glycinate, sodium gluconate, sodium glutamate, sodium hydroxymethane sulfonate, sodium oxalate, sodium phenate, sodium propionate, sodium saccharin, sodium salicylate, sodium sarcosinate, sodium toluene sulfonate, magnesium aspartate, calcium propionate, calcium saccharin, calcium d-saccharate, calcium thioglycolate, aluminum caprylate, aluminum citrate, aluminum diacetate, aluminum glycinate, aluminum lactate, aluminum methionate, aluminum phenosulfonate, potassium aspartate, potassium biphthalate, potassium bitartrate, potassium glycosulfate, potassium sorbate, potassium thioglycolate, potassium toluene sulfonate, and magnesium lactate.
Alcohol Component
The term xe2x80x9calcoholxe2x80x9d as used herein is intended to mean a lower alkyl alcohol such as ethanol. Examples of some other appropriate lower alkyl alcohols which can be used are methyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, and isobutyl alcohol. Generally, these lower alkyl alcohols will contain one to about four carbon atoms.
Solvent Component
Solvents which can be used herein include alkanes with generally less than about 16 carbon atoms such as pentane and hexane; ketones such as acetone, methyl ethyl ketone, methyl n-butyl ketone, and methyl amyl ketone; aromatic compounds such as benzene, toluene, and ethylbenzene; esters such as ethyl acetate, isopropyl acetate, methyl acetoacetate, and isobutyl isobutyrate; ethers such as ethyl ether, butyl ethyl ether, isopentyl ether, propylene oxide, and tetrahydrofuran; glycols such as ethylene glycol, propylene glycol, and diethylene glycol; and chlorinated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, ethyl chloride, and chlorobenzene.
Emulsion Preparation
The mechanical preparation of an emulsion involves mixing water, one or more surfactants, and an oil, and homogenizing the mixture using a laboratory homogenizer or other device for applying vigorous agitation. The silicone polyether can be incorporated in the mechanical process as the sole emulsifier, or it can be used with a co-surfactant such as another organic surfactant. Alternatively, the silicone polyether can be post-added to a previously prepared emulsion.
The process of preparing emulsions by the emulsion polymerization process involve mixing water, surfactant(s), and oil monomers, with a polymerization catalyst. The mixture is agitated until essentially all of the oil monomer is reacted and consumed, and a stable emulsion or microemulsion is formed. The silicone polyether is preferably incorporated before polymerization occurs, i.e., before the catalyst is added. The post addition of the silicone polyether to emulsions prepared by emulsion polymerization has been found to be less effective in providing salt, alcohol, and solvent stability.
In particular, this method of making such organic oil-in-water emulsions involves (i) preparing an aqueous phase containing water, a silicone polyether surfactant, and optionally one or more organic surfactants; (ii) preparing an oil phase comprising a non-silicon atom containing unsaturated organic monomer; (iii) combining the aqueous phase and the oil phase, and applying shear; (iv) adding a polymerization catalyst to the combined phase; (v) agitating the combined phase for a time sufficient to allow the non-silicon atom containing unsaturated organic monomer to polymerize to an organic polymer of the desired molecular weight; and (vi) recovering the organic oil-in-water emulsion containing the organic polymer in the oil phase of the organic oil-in-water emulsion.
Such emulsions, whether prepared mechanically or by emulsion polymerization, typically have their pH adjusted to 6-7.5, and in general contain 5-80 percent by weight of oil, preferably 20-60 percent; 0.1-20 percent by weight of the surfactant(s), preferably 0.1-10 percent; and 20-90 percent by weight of water, based on the weight of the emulsion.
Optional Components
Since emulsions are susceptible to microbiological contamination, a preservative may be required as an optional component of the emulsion, and some representative compounds which can be used include formaldehyde, salicylic acid, phenoxyethanol, DMDM hydantoin (1,3-dimethylol-5,5-dimethyl hydantoin), 5-bromo-5-nitro-1,3-dioxane, methyl paraben, propyl paraben, sorbic acid, imidazolidinyl urea sold under the name GERMALL(copyright) 11 by Sutton Laboratories, Chatham, N.J., sodium benzoate, 5-chloro-2-methyl-4-isothiazolin-3-one sold under the name KATHON CG by Rohm and Haas Company, Philadelphia, Pa., and iodopropynl butyl carbamate sold under the name GLYCACIL(copyright) L by Lonza Incorporated, Fair Lawn, N.J.
A freeze/thaw stabilizer can be included as an optional component of the emulsion including compounds such as ethylene glycol, propylene glycol, glycerol, trimethylene glycol, and polyoxyethylene ether alcohols such as products sold under the name RENEX 30 by ICI Surfactants, Wilmington, Del.
Another optional component of the emulsion which can be included is a corrosion inhibitor such as an alkanolamine, an inorganic phosphate such as zinc dithiophosphate, an inorganic phosphonate, an inorganic nitrite such as sodium nitrite, a silicate, a siliconate, an alkyl phosphate amine, a succinic anhydride such as dodecenyl succinic anhydride, an amine succinate, or an alkaline earth sulfonate such as sodium sulfonate or calcium sulfonate.
Compositions
A first composition which can be prepared according to the concept of the present invention contains:
(i) 1-30 percent by weight of the salt component, and
(ii) 70-99 percent by weight of the organic O/W emulsion, which as noted above, contains 5-80 percent by weight of the organic oil, 0.1-20 percent by weight of the surfactant(s), and 20-90 percent by weight of water. This first composition is in the form of an O/W emulsion.
A second composition which can be prepared according to the concept of the present invention contains:
(i) 1-80 percent by weight of the alcohol component, and
(ii) 20-99 percent by weight of the organic O/W emulsion, which as noted above, contains 5-80 percent by weight of the organic oil, 0.1-20 percent by weight of the surfactant(s), and 20-90 percent by weight of water. This second composition is in the form of an O/W emulsion.
A third composition which can be prepared according to the concept of the present invention contains:
(i) 1-99 percent by weight of the solvent component, and
(ii) 1-99 percent by weight of the organic O/W emulsion, which as noted above, contains 5-80 percent by weight of the organic oil, 0.1-20 percent by weight of the surfactant(s), and 20-90 percent by weight of water. This third composition is in the form of a two-phase system wherein one phase contains the solvent and the other phase contains the stable O/W emulsion; or it can be in the form of a homogeneous single phase containing the solvent and the stable O/W emulsion.
A fourth composition which can be prepared according to the concept of the present invention contains:
i) 1-30 percent by weight of the salt component,
(ii) 10-80 percent by weight of the alcohol component,
(iii) 1-80 percent by weight of the solvent component, and
(iv) 10-90 percent by weight of the organic O/W emulsion, which as noted above, contains 5-80 percent by weight of the organic oil, 0.1-20 percent by weight of the surfactant(s), and 20-90 percent by weight of water. This fourth composition is in the form of an emulsion.
When it is desired to include an optional component in these compositions, 0.01-0.1 percent by weight of each optional component, i.e., preservative, freeze/thaw stabilizer, or corrosion inhibitor, can be added to the composition.
Such compositions can generally be prepared at room temperature using simple propeller mixers, turbine-type mixers, Brookfield counter-rotating mixers, or homogenizing mixers. No special equipment or processing conditions are generally required.
Stability Measure
Emulsion stability was evaluated by visual observation. Emulsion instability was determined as being indicated by the emulsion separating into an oil-rich and a water-rich layer or sedimentation. Only the initial stability was determined in the examples. However, many of the formulations showed long term stability of the order of weeks and months.